Planetary rolling contact gears are being used more and more in drive systems and components. A relative rotation between the spindle nut and the threaded spindle is converted into an axial displacement between the spindle nut and the threaded spindle. Between the threaded spindle and the spindle nut there are planets that are arranged distributed over the periphery and roll on the threaded spindle and on the spindle nut with the relative rotation.
From DE 102010011819, a planetary rolling contact gear is known. The planet has a middle section with a greater diameter along its planet axis and end sections with a smaller diameter on both sides of the middle section in the axial direction, wherein a first engagement profile is formed on the lateral surface of the planet in the middle section and a second engagement profile is formed in each of the end sections. The planets are in rolling engagement with their first engagement profile with a helical thread of the threaded spindle wound about the spindle axis. The planets are in rolling engagement with their second engagement profile with a nut-side engagement profile of the spindle nut.
The first engagement profile of the planet has a plurality of annular first teeth arranged about the planet axis, wherein first grooves arranged in the shape of a ring about the planet axis are formed between successive first teeth for an engagement of the thread of the threaded spindle, wherein a tooth contour is allocated to each of the teeth of the middle section. These first grooves are also designated as advance feed grooves, because the rolling engagement with the threaded spindle allows the relative advance feed between the threaded spindle and spindle nut. The second engagement profile has a plurality of second teeth arranged in a ring about the planet axis, wherein second grooves arranged in a ring about the planet axis are formed between successive second teeth. These second grooves are also designated as guide grooves, because the planets with these second grooves are in rolling engagement with the nut-side engagement profile and are guided on a circular path about the spindle axis into the spindle nut.
While the planetary rolling contact gear is in operation, the planets can be loaded with axial forces that are transferred between the spindle nut and the threaded spindle via the engagement profiles. If the tips of teeth in the engagement profiles break off, a problem-free operation of the planetary rolling contact gear is disrupted.